Le 10/02/2022 à 02:34, aitor a écrit :
>
> Hi Didier,
>
> On 9/2/22 16:36, Didier Kryn wrote:
>> And, if you haven't a server like ifupdown or netplug, you're going
>> to need to restart networking everytime you plug/unplug your Ethernet
>> cable.
>
> Well, you mean *ifplugd* or netplug..., I understand.
>
    Yep (~:
>
> Try with "auto" and "allow-hotplug" together, both at once. That is:
>
> auto eth0
> allow-hotplug eth0
> iface eth0 inet dhcp
>
> With this configuration, plug/unplug events will be automatically
> detected.
>
    Maybe plug/unplug of devices are detected, but I doubt plug/unplug
of Ethernet cable are, though I didn't try because I should have
uninstalled ifplugd for the test to be conclusive.

    But I made a minimum testing: I just inserted the doube stanza you
suggest, for the eth0 interface of my laptop, and the net effect on
reboot is a long delay with the message that ifup is waiting for a lock
file the name of which contains "eth0". I would have bet some bucks on
this result (~:

    My normal interfaces file contains an "auto" stanza for wlan0,
which is superfluous, according to messages from ifplugd, and *only*
"iface eth0 inet dhcp" for eth0 because it comes first in the file and
"auto" and/or "allow-hotplug" can just cause the abovementionned delay
when no Ethernet cable is connected. Again, "auto" and/or
"allow-hotplug" are useless when you have ifplugd managing eth0 and
wlan0; they can only cause a startup delay. Even on my desktop, which
only has an Ethernet connection, eth0 is managed by ifplugd and there is
no "auto" or "allow-hotplug" stanza. This allows smooth functionning
when the machine is moved around and the Ethernet cable
plugged/unplugged and/or the DSL modem/router is restarted.

> I'll answerin detail to the rest of your post shortly, when I have time.
>
    I'd like a lot to learn more on this. I reached a consistent
understanding based on experiments, but it's certainly not definitive
and I know you're looking at things more in depth.

    Cheers.

--     Didier